A project which began taking shape in 2020, Akre recently achieved its aim of establishing the world’s first verified carbon-negative tree nursery. Forestry Journal paid a visit to its cutting-edge glasshouse tree nursery in Fife to learn how its proprietary blend of technology can be used to produce the highest-quality, lowest-impact trees on the market.

THREE years on from meeting up with Renwick Drysdale and Kieran Kelly at KF Forestry based near Kirkcaldy in Fife, Forestry Journal caught up with them again to visit the world’s first verified carbon-negative tree nursery.

At the time of that first visit in the autumn of 2020, Renwick had outlined their plans, explaining how they had set up a new business called Kirlie Trees with the aim of “producing trees and offering a consultancy service to allow landowners, business, and investors to benefit from the carbon market”.

The business is now called Akre and it operates as a natural capital solutions company with a stated mission to “help organisations help the planet”, believing “that business and nature are not mutually exclusive and that a better economic system, one that creates value and enhances nature simultaneously, is possible”.


This is done through “delivering and managing ecological restoration plans for communities, landowners, funds and investors”, supported by “the world’s first verified carbon-negative nursery built to overcome the challenges surrounding tree seed supply and seed provenance” and finally by “maintaining an offset exchange platform that connects business to nature-based projects”.

The change of name from Kirlie Trees to Akre, as Renwick explained, was carried out in light of the stated aims and objectives of the business. He said: “We are about more than just trees. We aim to enhance every acre we interact with, be that peatland, wetland, grassland, moorland, or woodland restoration. Trees are part of this process, but just having this in the business name was too restrictive when explaining what we do. The glasshouse at our nursery covers an acre of land and our stated goal is to improve acres of land in the future, so the name ‘Akre’ seemed appropriate.”

Renwick sought advice in the early days from Rodney Shearer on the setting up of a nursery, and consulted widely with Forestry England, Scottish Forestry and the Scottish Agricultural College. Since then, Akre has been delighted to bring on board Mark O’Neill as director of research and development, who, when working for Maelor Forest Nurseries, was involved in the setting up of a tree nursery just outside Wrexham. 

Forestry Journal: The Ellepot Flexline, which prepares the paper pots for sowing.The Ellepot Flexline, which prepares the paper pots for sowing. (Image: FJ)

He was seen as a great fit for Akre, bringing with him a wealth of useful experience.

“Securing Mark within the team emphasises how well received Akre’s approach has been within the industry and lays the foundation for future expansion,” said

Renwick. “Mark’s appointment builds out the core team of James Patterson, the nursery manager, and David Farrow, the senior project manager. We have also added a software developer, Craig Coventry, in recent months to ensure our approach is truly data driven.” 

The evolution of the nursery, since FJ’s visit in 2020, when the plans and ideas were being formulated and agreed, was quick and captured in a series of milestone pictures by Renwick. March 2021 saw the area at the nursery site being dug out. The following month the team came on site and by September the building foundations were going in. April 2022 saw the ‘cutting off’ of the last piece of metal and the structure of the nursery completed. The first trees were planted in 2022.

Akre has undertaken its own carbon journey to achieve the status of being the world’s first verified carbon-negative tree nursery. The steps taken included contacting the Energy Savings Trust, which assigned an energy consultant who carried out a carbon audit of the nursery and its supply chain. This audit showed emissions were 342.8 CO2e (carbon dioxide equivalent). The audit also outlined that by using a combination of LED lighting, solar photovoltaic panels, battery storage and renewable heating, this figure could be reduced to 92.56 CO2e – a 77-per-cent reduction.

The final step in the journey was for Akre to purchase 250 verified woodland carbon units from a biodiverse carbon-negative woodland restoration project that had been retired against these emissions. This allowed the claim to be made that Akre is currently carbon negative. This will be an ongoing process with the strategy to purchase credits again after three years to offset ongoing emissions. There is also a process in place to continue reviewing ways to reduce the nursery emissions with a yearly audit being conducted and ways to make reductions being investigated. Akre has published its working and reports on its website to demonstrate transparency and encourage others to take a similar approach.

 “As a business that is dealing with the carbon impact it was imperative that we ourselves were doing everything we could to mitigate our impact,” said Renwick.

“The Energy Savings Trust were helpful, not only in putting us in touch with an energy consultant to help us identify the ways to mitigate our carbon impact, but they also supplied us with an interest-free loan which we were able to use to purchase the solar panels and batteries needed to power the nursery.”

Forestry Journal:  Kieran and Renwick. Kieran and Renwick. (Image: FJ)

Akre’s nursery is self-sufficient for energy, which is produced on site using a combination of solar and battery power. When the energy coming from the solar panels is not required for the nursery it is used to charge up the batteries and then, if there is surplus, it is offered to the national grid. LED grow lights, which are both energy efficient and aid growth, are used in the glasshouse to ensure the highest level of quality in the trees produced.

Renwick said: “The lights increase the amount of photosynthetically active radiation the plants get at either end of the day, which allows them to grow more consistently and improves the quality of the trees and their root development.”

The propagation system was custom made by Ellepot from Denmark. It is a sustainable and environmentally friendly solution resulting in higher yields per plant, and allows for quicker transplanting and faster handling. Akre production methods also make use of Ellepot’s paper pot system, which helps, in both quality and in the production of excellent root systems. These pots can be fitted into the Proptek trays used by the nursery.

Forestry Journal:  Renwick with a native Caledonian pine tree from Glen Feshie demonstrating the great root system achieved with air pruning. Renwick with a native Caledonian pine tree from Glen Feshie demonstrating the great root system achieved with air pruning. (Image: FJ)

Proptek trays have been developed and scientifically designed to facilitate techniques such as air pruning, which Akre employs at the nursery. Air pruning helps better root making and branching, in effect allowing the whole pot to be filled with roots, but not in a tangle. This also helps the trees in the nursery to absorb water and nutrients better and, when transplanting takes place, the root structure is in a much better position to help the trees succeed and grow.

“As well as working closely with Ellepot to ensure that we could develop this innovate environmentally controlled system to grow our trees in, we have also been in touch with Wageningen University and Research in the Netherlands,” said

Renwick. “They are a public research university, which is recognised as a world-renowned centre for life sciences and agricultural research. They are a vehicle to ensure that any scientific breakthroughs are put into practice and education.

“While more agriculture than trees, we have been able to see what they are doing and, in turn, we will feedback into them the results of work at Akre.”

Forestry Journal: James Patterson, nursery manager, running the seeding line.James Patterson, nursery manager, running the seeding line. (Image: FJ)

As well as being self-sufficient for power, the nursery is also off-grid for water, collecting rainwater and recycling it on site. The glasshouse is also of a modular design, so it could be added to or indeed set up elsewhere. Air pruning, while it is still early days, is producing trees to plant out that are achieving up to a 40-per-cent greater success rate in terms of establishment.

Renwick said: “We are also finding that they can be up to six times less susceptible to drought impacts, something that is going to become a major factor in the future as the impact of climate change affects more. One of the major differences though at Akre is that we have built our own software development capacity to help us develop our proprietary environmental control system. Craig Coventry, our software developer, has been developing and working on software to allow us to achieve optimal conditions for growing our trees. We are also gathering all our data and using machine learning to improve our systems constantly.

“We have internal and external sensors, which monitor the conditions, and we can change the internal conditions to reflect what is happening outside the glasshouse.

"We can open and shut vents in the roof, we can change light settings inside, and we can use screens inside to vary the light levels. We have a mobile irrigation system inside that allows us to water as required and we can control the humidity levels inside to suit the needs. In short, through the use of technology we can create the best growing conditions.” 

While Akre can have the best environment to grow the trees at its nursery, the seed-collection process is vital to its overall success. Akre uses its own teams, from KF Forestry, to collect and return seeds from land to where they will grow to ensure provenance and success. Other seeds are from Forestart in Shropshire.

Forestry Journal:  Caledonian Scots pine from Glen Feshie growing in the nursery. Caledonian Scots pine from Glen Feshie growing in the nursery. (Image: FJ)

“Forestart collects seeds from around the UK from known sites and it also has its own seed orchards,” said Renwick. “It can supply full provenance of its seeds and can supply what we need, offering a great service. So having the right seeds and then growing them in our nursery, in the right conditions, we believe allows us to help optimise the success of the future woodlands that we will be involved in planting and supporting.”

Early 2023 saw a great deal of press and media coverage about the Akre nursery launch and I was interested to hear from Renwick how the journey had been since then.

“The launch was terrific and we got a lot of coverage, but since then we have been very much focused on the trees,” he said. “This season we will produce 2.5 m trees with the target from 2024 to grow this figure to 6.4 m. These trees will be used both in our own tree-planting projects as well as for selling to other partners for use on their own woodland-creation schemes. 

“We can help manage this on their behalf and a lot of work to date has been engaging with others to explain what we can offer and inviting them to tour our nursery. We would like to ramp up production to 10 m trees in the future and these will be 90–95-per-cent native species, with Scots pine being the native conifer, although we plan next year to start some small batches of Douglas fir. A lot of the work at the moment is word of mouth and getting the message of what we can offer out in the public domain.”

Forestry Journal: The Ellepot drill unit transplanting alder trees.The Ellepot drill unit transplanting alder trees. (Image: Supplied)

In 2021, Akre announced the acquisition of Far Ralia, in Badenoch, on behalf of Abrdn’s Standard Life Investments Property Income Trust (SLIPIT) Fund. At the time, Renwick told Forestry Journal that he saw it as “a landmark step for the use of private capital in enhancing and regenerating landscape”. Far Ralia is 1,400 ha of non-productive open moorland and Akre has been working on a planting schedule which will see 1.2 m trees planted there in what will be one of the largest native woodland projects in Scotland.

“We have collected seed from there and neighbouring lands and supplemented this to grow these trees at our nursery. Initially there was a lot of ground preparation work after the seed collection, but we have now started planting with the aim to have this completed by the end of 2024. The species being planted are native upland species like pine, birch, aspen willow and alder, among many more. By the end we will have created 850 ha of woodland and 40 ha of montane scrub.”

During the summer of 2023 it was reported that new woodland created in Scotland had fallen by around 2,000 hectares year on year to below 9,000 ha, well short of the 15,000 ha/year target. Renwick and Akre welcomed the Rural Affairs Secretary Mairi Gougeon to the nursery at Kirkcaldy. They were able to show her at first hand what they were doing to help grow the trees that are needed to close this gap. Ms Gougeon also took the opportunity to announce a £1 m investment through Scottish Forestry for a new comprehensive skills training programme for frontline staff. Renwick warmly welcomed this.

 “Everyone needs to be sharpening their pencils when it comes to tree planting and woodland creation. The raising in the skill levels and developing knowledge of those frontline staff involved in agreeing projects can only be a good thing to get quicker approvals and ensure more urgency around the woodland-creation projects. We want to play our part at Akre and are grateful for the support that we have had in the form of grants from Scottish Forestry to assist with the purchase of some of the capital equipment in the nursery.”

One trillion trees are required globally to be planted by 2050, which gives an idea of the scale of the issue. Akre has developed a solution to this, but it requires 720 nurseries that produce 30 million trees a year to have been built last year to meet these targets. Every year that passes without capacity increasing adds to the deficit.

Forestry Journal:  Renwick talking trees with Scotland’s Rural Affairs Secretary Mairi Gougeon. Renwick talking trees with Scotland’s Rural Affairs Secretary Mairi Gougeon. (Image: Supplied)

Renwick said: “We have shown that it is possible to improve tree propagation, produce trees of the highest quality and do it in a carbon-negative tree nursery. We exist to deliver on these targets as efficiently as possible and to ensure we maximise their positive impact.

“We are at a pivotal point in our history. If we choose to, we can make ours the generation that halted our negative impact on the natural systems we depend on and started to help them thrive.”